The proposed research will study factors that influence the abuse liability of sedative drugs. The research will (1) assess relative preference for representative sedative compounds using a human drug self-administration choice procedure, (2) identify variables which contribute to marked individual differences in human sedative self-administration, (3) identify variables that control human sedative self-administration and (4) assess the effectiveness of behavioral procedures for modifying sedative drug intake and preference. The results of these investigations are expected to improve our understanding of the behavioral and pharmacological variables that determine the abuse liability of sedative drugs.